I went through this when Ray passed away. Each person grieves in their own way, so be prepared to follow her lead on some of this, but also be ready to take charge if she is struggling. You will know if there is a problem if her grades change, her habits change, she gets in trouble when she never did before. Children who have lost a parent can get free grief counseling from Hospice. Each Hospice group is run differently, you will need to talk to a non-profit one.
As far as raising a teenager, talk to her every chance you get. Teenagers are learning to become adults, and they have a lot of situations that they need guidance through, and the more you are able to talk, the easier it will be when something hard happens for her to come to you for help. Make sure you know who her friends are, and make friends with them too (food is generally a great ice breaker). They are a huge part of her support system at this age.
Be patient with yourself, it is ok to make mistakes, and it is ok to tell her, I don't know, but I'll find out and we can work it out together. It's also important to be able to tell her you love her even if you don't always agree. And try to take care of your husband and yourself. The first time I got really sick after Ray died, Joshua panicked, it was really really hard for him.
Good luck!